I've played it for a few minutes and reached the following conclusions:
The 3D map is completely pointless, and it feels like it was implemented just so that they could advertise the game as being 3d. Personally, aesthetically speaking, I liked the 2D from the previous games better.
The tutorials are of the "read text" variety as opposed to the "learn as you play" variety. I guess it may help some people that have played previous Paradox games. However, I think someone new to the game will gather exactly bugger all from going through the tutorials.
As for the game itself, I only played it for a year, but from what I saw, the military works as before, colonizing works as before and trade works a before. Diplomacy however, seems to be a bit deeper, giving you more options at least than it did in EU1. The overall nation controls are another part of the game that seem to have more options. Specifically, I don't remember the advisor screen, and the religious toleration screen.
Of course EU3 will be made or broken by the quality of the AI, and as such I'll have to delve deeper into the game to see how the AI dares.